Coil winding method and a combination of a coil winding jig and a coil winding machine for carrying out the same

Abstract: A coil winding jig (5), a coil winding machine employing the coil winding jig, and a coil winding method to be carried out by the coil winding machine are provided. The coil winding jig (5) comprises: a first block (50) having a first flange (50a) to which the free end of the wire is fixed; a second block (51) having a second flange (51a) and disposed opposite to and coaxially with the first block (50) with the front surface of the second flange (51a) facing the front surface of the first flange (50a) and spaced apart a distance corresponding to the width (w) of the coil (C) to be formed from the front surface of the first flange (50a); a third block (52) disposed coaxially with the second block (51), having a middle portion contained within the second block (51), and a coil form (52a) having a front end to be pressed against the first flange (50a) and projecting from the middle portion through a hole (51c) formed in the second flange (51a) toward the first flange (50a) of the first block (50). The coil form (52a) is tapered toward the first flange (50a), has an outer circumference consisting of inclined side surfaces (T) and is provided with steps (55) having a size smaller than the diameter of the wire on its side surfaces contiguously with the front surface of the second flange (51a).

Description: BACKGROUND OF THE INVENTION The present invention relates to coil winding method of forming a coil for a flat motor or such and a combination of a coil winding jig and a coil winding machine for carrying out the coil winding method. When forming a coil having a polygonal cross section, i.e., what is called a Vicks coil, by winding a wire, for example, for a flat motor, a coil winding jig holding a coil form between a pair of flanges must be rotated to wind a first layer, a second layer, ... and n-th layer sequentially. The spirals of the wire in the second layer and the following layers must be formed between the spirals of a wire in the underlying layer in a mutually interposed arrangement to form each layer in a regular arrangement of spirals. Since a fixed tensile force is exerted on the wire when winding the wire in a coil, the first spiral of the second layer is forced to fall between the last spiral of the first layer underlying the second layer and the flange and, consequently, the spirals of the second layer cannot be formed regularly in a mutually interposed arrangement over the first layer entailing irregular arrangement of spirals of the wire in the third layer and the following layers, so that a random coil is formed. Since a tensile force is exerted on the wire when the wire is wound on the coil form, the coil squeezes the coil form firmly and hence a large force must be applied to the coil to remove the coil from the coil form. There is disclosed in document DE-B-1 564 485 a coil winding apparatus comprised of a core, a first fixed flange and a second detachable flange. The latter flange is provided with a collar member at a position corresponding to the start of the first spiral of the first coil layer. The member is formed with a guiding groove which serves to maintain the first and subsequent windings orthogonal to the core. There is also known from document US-A-4 668 544 a coil winding apparatus in which there is provided a coil form which presents a polygonal cross section with an acute angle between two opposite side surfaces. Finally, there is disclosed in document DE-C-25 65 33 a coil winding apparatus in which the core winding block is provided with a bore at an end portion for receiving a pin having an enlarged and rounded head that projects onto the coil receiving surface of the core at a region next to the flange. The profile of the head is made to be rounded and have a width corresponding to half a diameter of the wire to be wound. SUMMARY OF THE INVENTION The present invention has been made in view of such problems in the conventional coil winding method and it is therefore an object of the present invention to provide a coil winding method and a combination of a coil winding jig and a coil winding machine capable of forming spirals of a wire in a regular arrangement in each of a plurality of layers and of enabling a coil formed on a coil form to be easily removed from the coil form. With the foregoing object in view, the present invention provides a coil winding jig to be rotated to wind a wire under a fixed tension into a coil formed thereon, comprising : a first block having a first flange to which the free end of the wire is fixed; a second block having a second flange, and disposed opposite to and coaxially with the first block with the front surface of the second flange facing the front surface of the first flange and spaced apart therefrom by a distance corresponding to the width of the coil to be formed; a third block disposed coaxially with the second block, having a middle portion contained within the second block, and having a coil form having a front end to be pressed against the first flange and projecting from the middle portion through a hole formed in the second flange of the second block toward the first flange of the first block; characterized in that the coil form is provided, on its side surfaces, with step means which are contiguous with the front surface of the second flange of the second block; and in that the second block having the second flange, is axially movable relative to third block having the coil form. Preferably, the coil form is tapered toward the first flange and the outer surface of the coil form consists of inclined side surfaces. Preferably, the step means comprise plural steps. Preferably, the coil to be formed on the coil winding jig is a coil having a polygonal cross section for a flat motor, and the steps are formed on opposite inclined side surfaces of the coil form and around the opposite edges of the inclined side surfaces. The present invention further provides a coil winding machine comprising: the above-mentioned coil winding jig; a driving source for moving the first block toward and away from the second block; a torque transmitting means for transmitting the torque of the first block through the coil form of the third block to the second block; and a tensioning means for keeping the wire under a fixed tension while the wire is being fed to the coil form of the third block. The present invention provides also a coil winding method employing a coil winding jig of the type defined above and comprising the steps of: winding a wire around the coil form from the side of the first flange toward the second flange so that spirals of the wire are formed contiguously in a first layer; winding the first spiral of the wire of a second layer on the steps of the coil form; and once the winding of said wire on said coil form is completed, removing said coil form by removing the second block of said winding jig relative to the third block thereof by movement in an axial direction. The spirals of the first layer are formed on the coil form from the side of the first flange toward the second flange, and then the spirals of the second layer are formed between the adjacent spirals of the first layer from the side of the second flange toward the side of the first flange. Since the first spiral of the second layer is wound around the steps, the first spiral of the second layer is not forced to fall between the last spiral of the first layer and the second flange to form the spirals of the second layer and the following layers in an irregular arrangement, so that a random coil will not be formed. Since the first spiral of the second layer is formed in a correct spiral, the second spiral and the following spirals of the second layer can be regularly formed between the adjacent spirals of the underlying first layer. Since the coil form is tapered toward the first flange and the surface of the coil form consists of the inclined side surfaces, the spirals of the first layer wound around the coil form tend to move toward the first flange and hence the spirals of the first layer are formed contiguously with each other in an accurate arrangement. Accordingly, the spirals of the second layer and the following layers are not arranged irregularly and the coil thus formed can be easily moved toward the first flange to remove the coil from the coil form. BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become more apparent from the following description taken in connection with the accompanying drawings, in which: Fig. 1 is a longitudinal sectional view of an important portion of a coil winding jig in a preferred embodiment according to the present invention; Fig. 2 is a sectional view taken on line A-A in Fig. 1; Figs. 3(a) and 3(b) are pictorial views of assistance in explaining a mode of forming layers of spirals of a wire when a conventional coil winding jig is used and Figs. 3(c) and 3(d) are pictorial views of assistance in explaining a mode of forming layers of spirals of a wire when the coil winding jig of Fig. 1 is used; Fig. 4 is a perspective view of a coil winding machine provided with the coil winding jig of Fig. 1; Fig. 5 is a fragmentary, longitudinal sectional view of the coil winding machine of Fig. 4, showing the coil winding jig of Fig. 1 and the associated parts; and Fig. 6 is a sectional view of a coil formed on the coil form of the coil winding jig of Fig. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to Fig. 4 showing a coil winding machine for forming a coil having a polygonal cross section for a flat motor, an insulated wire L is wound on a bobbin 1 and the bobbin 1 is supported for rotation about an axis 1a. The wire L pulled out from the bobbin 1 is extended through a tension device 2 for exerting a fixed tensile force on the wire L, an alcohol applicator 3 and a traverse guide 4, and the extremity of the wire L is fixedly held by a chuck 6 attached to the side surface of a first block 50 included in a winding jig 5. The alcohol applicator 3 applies an alcohol to the wire L to make the spirals of the wire L wound in a coil C adhere to each other. A transfer chuck 7 is disposed between the traverse guide 4 and the chuck 6 to take the extremity of the wire L to the chuck 6. The first block 50 of the coil winding jig 5 is fixed to the front end of a spindle 9 supported for rotation on the front support plate 8a and the back support plate 8b of a feed stand 8. A belt 11 is extended between the rear end of the spindle 9 and the driving shaft of a motor 10 held on the feed stand 8. The feed stand 8 can be moved forward and backward along a pair of rails 13 fixed to a base plate 12 by a driving source, not shown. As shown in Fig. 5, the coil winding jig 5 comprises, in addition to the first block 50, a second block 51, a third block 52, a compression spring 53 biasing the second block 51 toward the third block 52, and a flat pin 54, i.e., a torque transmitting means, for transmitting the rotation of the first block 50 to the third block 52. The first block 50, the second block 51 and the third block 52 are arranged coaxially. The first block 50 has a boss extending to the left, as viewed in Fig. 5, and joined to the spindle 9 and a first flange 50a formed in its front portion. The second block 51 has a second flange 51a formed in its front portion opposite to the first flange 50a of the first block 50, and a boss 51b in its back portion. The third block 52 has a middle portion slidably fitted in the boss 51b of the second block 51, and a coil form 52a projecting toward the first flange 50a of the first block 50 through a hole 51c formed in the second flange 51a of the second block 51. The compression spring 53 is compressed between the middle portion of the third block 52 and the back wall of the boss 51b within the boss 51b of the second block 51. The flat pin 54 projects from the center of the first flange 50a of the first block 50 toward the second flange 51a of the second block 51 so as to be fitted in a recess formed in the coil form 52a of the third block 52 to transmit the rotation of the first block 50 through the third block 52 to the second block 51. As shown in Fig. 6, the coil form 52a of the third block 52 has a substantially trapezoidal cross section, and the hole 51c of the second block 51 has a corresponding shape. Accordingly, the rotation of the third block 52 caused by the first block 50 causes the second block 51 to rotate. The flat central portion of the front surface of the first flange 50a of the first block 50, the outer surface of the coil form 52a of the third block 52 pressed against the first flange 50a, and the flat central portion of the front surface of the second flange 51a of the second block 51 facing the flat central portion of the front surface of the first flange 50a define a coil forming space S. The respective peripheral portions of the front surfaces of the first flange 50a and the second flange 51a surrounding the central flat portions of the same are tapered toward each other to facilitate the insertion of the wire L into the coil forming space S. As shown in Fig. 5, the third block 52 has a shaft extending backward, i.e., away from the coil form 52a, from the middle portion through the back wall of the boss 51b of the second block 51; this shaft is supported coaxially with the spindle 9 on a support pipe 14 supported in a radial bearing 15, a needle bearing and a thrust bearing 17 fitted in a bearing housing 16. The bearing housing 16 is held fixedly on a bracket 19 fixed to a bed 18. A cylinder actuator 20 is held on the bracket 19. The cylinder actuator 20 retracts the second block 51 of the coil winding jig 5 through an ejector 21 against the resilience of the compression spring 53 to remove a coil C from the coil form 52a. In operation, first the feed stand 8 is advanced, namely, moved toward the second block 51, to press the first flange 50a of the first block 50 mounted on the front end of the spindle 9 against the extremity of the coil form 52a of the third block 52 supported on the bearing housing 16 as shown in Fig. 5 to form the coil forming space S by the first block 50, the second block 51 and the third block 52 of the coil winding jig 5. In this state, the extremity of the flat pin 54 is fitted in the recess of the coil form 52a of the third block 52, so that the coil winding jig 5 can be driven for rotation by the spindle 9. Then, the free end of the wire L is transferred from the transfer chuck 7 to the chuck 6, and then the motor 10 is started to rotate the spindle 9 in the direction of the arrow (Fig. 4) through the belt 11. Consequently, the chuck 6 holding the free end of the wire L revolves together with the coil winding jig 5 to guide the wire L along the front surface of the first flange 50a of the first block 50 to the front end of the coil form 52a of the third block 52. Thus, the first spiral is formed around the front end of the coil form 52a, and then the second and the following spirals of the first layer are formed sequentially from the side of the first flange 50a toward the side of the second flange 51a. After the last spiral of the first layer has been formed, the wire L is caused to move toward the first flange 50a by the surface of the second flange 51a, so that spirals of the second layer are formed. After the last spiral of the second layer has been formed, the wire L is caused to move toward the second flange 51a by the surface of the first flange 50a, so that the spirals of the third layer are formed. Similarly, spirals of the fourth and the following layers are formed. Finally, a coil C having a thickness t and a width w as shown in Figs. 5 and 6 is formed on the coil form 52a. A tensile force is exerted by the tension device 2 on the wire L unwound from the bobbin 1 and an alcohol is applied to the wire L by the alcohol applicator 3. Therefore, the spirals of the wire L of the coil C adhere to each other. Upon the completion of winding operation, the motor 10 is stopped, the wire L is cut at a position near the coil C, and then the feed stand 8 is retracted to separate the first flange 50a of the first block 50 from the coil form 52a of the third block 52. Then, the cylinder actuator 20 is actuated to move the second block 51 of the coil winding jig 5 against the resilience of the compression spring 53 toward the first flange 50a by the ejector 21 and, consequently, the coil C wound around the coil form 52a is shoved off the coil form 52a by the second flange 51a. The coil winding jig 5 of the coil winding machine will be described in detail hereinafter with reference to Figs. 1, 2 and 3(a) to 3(d). Referring to Figs. 1 and 2, a pair of substantially U-shaped guide members 55 are attached closely to the circumference of the coil form 52a of the third block 52 so as to extend around the hole 51c of the second block 51 and to form a step near the back end of the coil form 52a in the coil forming space S. The guide members 55 are extended along the opposite inclined side surfaces 52a-1 and around the edges at the opposite ends of the inclined side surfaces 52a-1 as shown in Fig. 2. Each guide member 55 has a rectangular cross section and its height from the side surface of the coil form 52a is smaller than √3 d/2 and its width, i.e., height from the surface of the second flange 51a, is smaller than d/2, where d is the diameter of the wire L. The coil form 52a of the third block 52 is tapered toward the first block 50, namely, the cross section of the coil form 52a is reduced toward the first block 50, so that the circumference of the coil form 52a consists of inclined side surfaces T inclined at an angle in the range of 1 to 2°. The function of the guide members 55 and the inclined side surfaces T of the coil form 52a of the third block 52 of the coil winding jig 5 will be described hereinafter with reference to Figs. 3(a) to 3(d). The width of the coil forming space S between the first flange 50a and the second flange 51a is slightly greater than an integral multiple of the diameter of the wire L to facilitate winding the wire L around the coil form 52a. If the coil winding jig 5 is not provided with the guide members 55 and the wire L is wound around the coil form 52a from the side of the first flange 50a toward the second flange 51a to form the first layer, a portion L 1 of the wire L forming the first spiral of the second layer is forced to fall by half between the second flange 51a and a portion L 2 of the wire L forming the last spiral of the first layer as shown in Fig. 3(a). Consequently, the spirals of the second layer and the following layers are arranged irregularly and the coil C is formed in a random coil as shown in Fig.3(b). When the coil winding jig 5 is provided with the guide members 55 to form a small step on the coil form 52a contiguously with the second flange 51a in the coil winding space S, the portion L 1 of the wire L forming the first spiral of the second layer is wound on the guide members 55 as shown in Fig. 3(c) and will not be forced to fall between the second flange 51a and the portion L 2 of the wire L forming the last spiral of the first layer. Accordingly, the spirals of the second layer and the following layers are arranged regularly and the coil C is formed satisfactorily as shown in Fig. 3(d). The function of the inclined side surfaces T of the coil form 52a will be described hereinafter. The coil form 52a is tapered toward the first flange 50a and the circumference of the coil form 52a consists of the inclined side surfaces T. Therefore, the spirals of the wire L of the first layer wound around the coil form 52a tend to move toward the first flange 50a. Therefore, the spirals of the wire L of the first layer on the coil form 52a are biased toward the first flange 50a and are formed contiguously at accurate pitches and hence the spirals of the wire L of the second layer and the following layers are formed regularly. Although the coil C holds firmly to the coil form 52a because a fixed tension is held on the wire L during winding operation, the coil C can be easily removed from the coil form 52a simply by moving the second block 51 relative to the third block 52 by a small force because the circumference of the coil form 52a consists of inclined side surfaces T. As is apparent from the foregoing description, the combination of the coil winding jig and the coil winding machine, and the coil winding method in accordance with the present invention are capable of winding the wire in regularly arranged spirals for every layer of the coil, and of winding the coil so that the coil can be easily removed from the coil form.

Claims: A coil winding jig (5) to be rotated to wind a wire (L) under a fixed tension into a coil (C) formed thereon, said coil winding jig comprising : a first block (50) having a first flange (50a) to which the free end of the wire (L) is fixed; a second block (51) having a second flange (5la), and disposed opposite to and coaxially with the first block (50) with the front surface of the second flange (5la) facing the front surface of the first flange (50a) and spaced apart therefrom by a distance corresponding to the width (w) of the coil to be formed; a third block (52) disposed coaxially with the second block (51), having a middle portion contained within the second block (51), and having a coil form (52a) having a front end to be pressed against the first flange (50a) and projecting from the middle portion through a hole (51c) formed in the second flange (51a) of the second block (51) toward the first flange (50a) of the first block (50); characterized in that the coil form (52a) is provided, on its side surfaces, with step means (55) which are contiguous with the front surface of the second flange (51a) of the second block (51); and in that the second block (51) having the second flange (51a), is axially movable relative to third block (52) having the coil form (52a). A coil winding jig (5) according to claim 1, wherein the coil form (52a) is tapered toward the first flange (50a), and the circumference of the coil form (52a) consists of inclined side surfaces (T). A coil winding jig according to claim 1, wherein the coil (C) to be formed by using the coil winding jig (5) has a polygonal cross section, and the step means (55) are adapted to extend along two opposite inclined side surfaces of the coil form (52a) and around the opposite edges of the two opposite inclined side surfaces. A coil winding jig according to claim 2, wherein at least the two opposite side surfaces of the coil form (52a) are flat surfaces, and the angle () formed between the extensions of the two opposite side surfaces is an acute angle. A coil winding jig (5) according to any one of claims 1 to 4, wherein said step means (55) comprise plural steps. A coil winding machine comprising : a coil winding jig (5) as defined in any one of the preceding claims; a driving source for moving the first block (50) toward and away from the second block (51); a torque transmitting means (54) for transmitting the torque of the first block (50) through the coil form (52a) of the third block (52) to the second block (51); and a tensioning means (2) for keeping the wire (L) under a fixed tension while the wire is being fed to the coil form (52a) of the third block (52). A coil winding method employing a coil winding jig (5) as defined in any one of claims 1 to 5, comprising steps of: winding a wire (L) around the coil form (52a) from the side of the first flange (50a) toward the second flange (51a) so that spirals of the wire are formed contiguously in a first layer; winding the first spiral of the wire of a second layer on the steps (55) of the coil form (52a); and once the winding of said wire on said coil form is completed, removing said coil form by removing the second block (51) of said winding jig (5) relative to the third block (52) thereof by movement in an axial direction. A coil winding method according to claim 7, wherein the coil form (52a) is tapered toward the first flange (50a), and the coil (C) formed on the coil form (52a) is moved toward the first flange (50a) in removing the same from the coil form.

Inventors: ISHIHARA MASAO, NAKAJIN MASATAKA, UJITA MINORU, ISHIHARA, MASAO, NAKAJIN, MASATAKA, UJITA, MINORU, ISHIHARA, MASAO, C/O SONY CORPORATION, NAKAJIN, MASATAKA, C/O SONY CORPORATION, UJITA, MINORU, C/O SONY CORPORATION
Applicants: SONY CORP, SONY CORPORATION
Application year: 1994
Main classification: H02K15
IPC codes: H02K15, H01F41